#include <bits/stdc++.h>

using namespace std;

#define int128 __int128_t
#define int long long
#define PII pair<int, int>
#define PDD pair<double, double>
#define fi first    
#define se second
#define lowbit(x) x & -x
#define all(x) x.begin(), x.end()
#define INF 0x3f3f3f3f3f3f3f3f
#define ls(x) x << 1
#define rs(x) x << 1 | 1
#define ull unsigned long long
std::mt19937_64 rng(std::chrono::steady_clock::now().time_since_epoch().count());

const int N = 1e6 + 10, M = 5e6 + 10, mod = 998244353;
const double eps = 1e-8;

int t, n, m, k;	
string sr;

void solve() {
	cin >> n;
	map<int, vector<int>> mp;
	for (int i = 1; i <= n; i++) {
		int x;
		cin >> x;
		mp[i - x].push_back(x);
	}
	int res = 0;
	for (auto [ke, va] : mp) {
		sort(all(va));
		for (int i = va.size() - 1; i >= 1; i -= 2) {
			int te = va[i] + va[i - 1];
			if (te >= 0) res += te;
			else break;
		}
	}
	cout << res << "\n";
}

signed main() {
	cin.tie(nullptr)->sync_with_stdio(false);
	//cout.setf(ios::fixed), cout.precision(8);
	t = 1;
	cin >> t;
	while (t--) {
		solve();
	}
	return 0;
}